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6.2. @Controller
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6.2. @Controller

	
package cn.netkiller.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class Welcome {

	@RequestMapping("/welcome")
	public ModelAndView helloWorld() {
		String message = "Helloworld!!!";
		return new ModelAndView("welcome", "message", message);
	}
}

6.2.1. @RequestMapping

		
@RequestMapping("/welcome")		
		
		
		
@RequestMapping(value = "/list", method =
RequestMethod.GET)

6.2.1.1. @RequestMapping("/")

			
package com.cf88.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/")
public class HelloController {

	@RequestMapping(value = "/{name}", method = RequestMethod.GET)
	public String getMovie(@PathVariable String name, ModelMap model) {
		model.addAttribute("name", name);
		return "hello";
	}

}

同時支持多種操作方法

			
	@RequestMapping(value = "/name", method = { RequestMethod.GET, RequestMethod.POST })

6.2.1.2. 映射多個URL

			
@RequestMapping({ "/news/zh-cn", "/news/zh-tw" })
@ResponseBody
public String getNewsByPath() {
	return "Hello";
}

6.2.1.3. 匹配通配符

			
@Controller
@RequestMapping("/test/*")

public class TestController {

	@RequestMapping
	public String default() {
		return "OK";
	}
}

6.2.1.4. headers

			
@RequestMapping(value = "/news/json", method = GET, headers = "Accept=application/json")
@ResponseBody
public String getFoosAsJsonFromBrowser() {
    return "{...}";
}
			
			
			
curl -H "Accept:application/json,text/html"
http://localhost:8080/spring/news/json.html

6.2.1.5. @GetMapping

@GetMapping 等效與 @RequestMapping

			
@RequestMapping(value = "/news/list", method = GET)

範例

			
import org.springframework.web.bind.annotation.GetMapping;

	@GetMapping("/finance/list")
	public String financeList() {
		return financeService.financeList();
	}
			
			
			
@GetMapping(value = "/user",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)

6.2.1.6. @PostMapping

@GetMapping 等效與 @RequestMapping

			
@RequestMapping(value = "/news/list", method = RequestMethod.POST)

範例

			
import org.springframework.web.bind.annotation.PostMapping;

	@PostMapping("/finance/list")
	public String financeList() {
		return financeService.financeList();
	}

Content-Type: multipart/form-data

			
@PostMapping(path = "/upload", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)

6.2.1.7. RequestMapping with Request Parameters - @RequestParam

@RequestParam 用來處理 HTTP GET/POST 請求的變數

				import
				org.springframework.web.bind.annotation.RequestParam;
6.2.1.7.1. HTTP GET
			
	@RequestMapping("/request/param")
	@ResponseBody
	public String getBarBySimplePathWithRequestParam(@RequestParam("id") long id) {
	    return "Get a specific Bar with id=" + id;
	}
			
				

				
http://localhost:8080/Spring/request/param.html?id=100
6.2.1.7.2. HTTP POST
			
package cn.netkiller.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class Http {

	@RequestMapping("/http/form")
	public ModelAndView createCustomer(){
		ModelMap model = new ModelMap();

		model.addAttribute("email", "netkiller@msn.com");
		model.addAttribute("phone", "13113668890");

	    return new ModelAndView("http/form", model);
	}

	@RequestMapping(value= "/http/post", method = RequestMethod.POST)
	public ModelAndView saveCustomer(HttpServletRequest request,
	        @RequestParam(value="Email", required=false) String email,
	        @RequestParam(value="Password", required=false) String password,
	        @RequestParam(value="Phone", required=false) String phone){

		ModelMap model = new ModelMap();

		model.addAttribute("email", email);
		model.addAttribute("password", password);
		model.addAttribute("phone", phone);

	    return new ModelAndView("http/post", model);
	}

}

http/form.jsp

			
<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>

	<form method="POST"
		action="http://localhost:8080/Spring/http/post.html" id="Register"
		name="Register">
		Email: <input class="register" type="text" id="Email" name="Email" value="${email}" /> <br />
		Password： <input class="register" type="password" id="Password" name="Password" value="" /><br />
		Phone： <input class="register" type="text" id="Phone" name="Phone" value="${phone}" /> <br />
		<input type="submit" id="btnRegister" name="btnRegister" value="Register" style="cursor: pointer" />
	</form>

</body>
</html>

http/post.jsp

			
<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	${email}<br>
	${password}	<br>
	${phone} <br>
</body>
</html>
6.2.1.7.3. @RequestParam 傳遞特殊字元串

URL 中 “+” 有特殊意義，表示空格。

如果 @RequestParam 傳遞參數含有空格可以這樣處理。

			
	@RequestMapping("/RequestParam")
	@ResponseBody
	public String query(@RequestParam("code") String code) {

		return code.replace(" ", "+");

	}
6.2.1.7.4. 傳遞日期參數
			
	@RequestMapping("/range")
	public ModelAndView range(@RequestParam("beginDate") @DateTimeFormat(pattern = "yyyy-MM-dd") Date beginDate, @RequestParam("endDate") @DateTimeFormat(pattern = "yyyy-MM-dd") Date endDate) {
		log.info("===== Begin ===== {}", beginDate);

		// 你的邏輯

		log.info("===== End ===== {}", endDate);
		return new ModelAndView("activity/index", "message", "操作成功");
	}
6.2.1.7.5. 上傳檔案
			
package cn.netkiller.restful;

import java.io.IOException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.multipart.MultipartFile;

@RestController
@RequestMapping("/upload")
public class UploadRestController {

	private static final Logger logger = LoggerFactory.getLogger(UploadRestController.class);

	public UploadRestController() {
		// TODO Auto-generated constructor stub
	}

	@PostMapping("/add")
	public String fileUpload(@RequestParam("file") MultipartFile multipartFile) throws IOException {

		String name = multipartFile.getOriginalFilename();
		System.out.println("File name: " + name);
		// todo save to a file via multipartFile.getInputStream()
		byte[] bytes = multipartFile.getBytes();
		System.out.println("File uploaded content:\n" + new String(bytes));
		return "file uploaded";
	}

}

操作演示，首先創建一個檔案

			
echo "Helloworld!!!" > hello.txt

上傳該檔案

			
neo@MacBook-Pro /tmp % curl "http://localhost:8080/upload/add" \                           
    -X POST \
    -H "Content-Type: multipart/form-data" \
    -F file=@"hello.txt"

file uploaded
6.2.1.7.6. @RequestParam - POST 數組

HTTP 頭

			
picture[]: gather/293a93baa02cb18a840631bac1f9eeb20b7d436f.jpeg
picture[]: gather/be7572e4df527b4389d605766ea65aafcf2d822a.jpg			
			
				
			
	@PostMapping("/save")
	public String save(@RequestParam(value = "picture[]", required = true) String[] picture) {
		return String.join(",", picture);
	}

6.2.2. @RequestBody

處理 raw 原始數據，例如提交的時 application/json, application/xml等

		
@RequestMapping(value = "/something", method = RequestMethod.PUT)  
public void handle(@RequestBody String body, Writer writer) throws IOException {  
	writer.write(body);  
}

6.2.2.1. @RequestBody 傳遞 List

			
package cn.netkiller.api.restful;

import java.util.List;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestRestController {

	@RequestMapping(value = "/test/list/{siteId}", method = RequestMethod.POST)
	public List<String> ping(@PathVariable("siteId") int siteId, @RequestBody List<String> tags) {
		System.out.println(String.format("%d, %s", siteId, tags));
		return (tags);
	}

}
			
			
			
$ curl -H "Content-Type: application/json" -X POST -d '["Neo","Netkiller"]' http://localhost:8440/test/list/22.json 

["Neo","Netkiller"]

6.2.2.2. 傳遞 Map 數據

			
	@PostMapping("/finance/list")
	public String financeList(@RequestBody Map<String,String> map) {
		return financeService.financeList(map);
	}
			
			
			
% curl -H "Content-Type: application/json" -X POST -d '{"date":"2017-11-08"}' http://localhost:8440/finance/list.json

6.2.3. @RequestHeader - 獲取 HTTP Header 信息

		
@RequestMapping("/displayHeaderInfo")  
public void displayHeaderInfo(@RequestHeader("Accept-Encoding") String encoding,  
                              @RequestHeader("Keep-Alive") long keepAlive)  {  
  
  //...  
  
}

獲取用戶當前語言

		
	@GetMapping("/lang")
	public String language(@RequestHeader("Accept-Language") String locale ) {
		System.out.println(locale);
		return locale;
	}

下面代碼可以獲得相同效果

		
	@GetMapping("/lang")
	public String language(Locale locale) {
		System.out.println(locale);
		return locale;
	}	
	
	@GetMapping("/lang")
	public String language() {
		String locale = LocaleContextHolder.getLocale().toString();
		System.out.println(locale);
		return locale;
	}

6.2.3.1. @RequestHeader 從 Http 頭中獲取變數

			
	@PostMapping(value = "/token")
	public TokenResponse token(@RequestParam String symbol, @RequestHeader String token) {
	
			TokenResponse tokenResponse = walletService.getTokenBySymbol(symbol);

			return tokenResponse;
	}

6.2.4. RequestMapping with Path Variables - @PathVariable

PATHINFO 變數可通過 @Pathvariable註解綁定它傳過來的值到方法的參數上。

6.2.4.1. URL 參數傳遞

需求，我們需要通過URL傳遞參數，所傳遞的值是分類ID與文章ID，例如 /news/1.html, /news/1/1.html。 

			
package cn.netkiller.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class Pathinfo {
	@RequestMapping("/pathinfo/{id}")
	public ModelAndView urlTestId(@PathVariable String id) {

		return new ModelAndView("pathinfo/param", "id", id);
	}

	@RequestMapping("/pathinfo/{cid}/{id}")
	public ModelAndView urlTestId(@PathVariable String cid, @PathVariable String id) {

		ModelMap model = new ModelMap();

		model.addAttribute("cid", cid);
		model.addAttribute("id", id);

		return new ModelAndView("pathinfo/param", model);
	}
}

jsp測試檔案

			
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
${ cid } <br>
${ id } <br>
</body>
</html>

6.2.4.2. 預設值

required 設置參數不是必須的

			
@PathVariable(required = false) String id

設置多個映射

			
@RequestMapping(value = {"/organization/{pageNumber}", "/organization"} , method = RequestMethod.GET)
public String list(@PathVariable(required = false) Integer pageNumber, ModelMap modelMap){
...
}

6.2.4.3. URL 傳遞 Date 類型

http://localhost:7000/history/2016-09-28%2000:00:00/

			
	@RequestMapping("/history/{datetime}")
	public String history(@PathVariable @DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss") Date datetime) throws Exception {

		System.out.println(datetime)

		return null;
	}

6.2.4.4. 處理特殊字元

http://www.netkiller.cn/release/1.0.1

			
@RequestMapping(value =	"/release/{version:[a-zA-Z0-9\\.]+}", method = RequestMethod.GET)
public @ResponseBody
	String release(@PathVariable String version) {
	log.debug("version: ", version);
	return version;
}

http://www.netkiller.cn/release/1.0.1/other

			
@RequestMapping(value="/release/{version:.+}",method=RequestMethod.GET)
public void download(HttpSession
	session,@PathVariable("version")String version){
	return version;
}

6.2.4.5. @PathVariable 注意事項

@PathVariable 參數傳統需要注意，參數中不能攜帶 “/”,斜杠會被視為目錄。

			
	@RequestMapping("/PathVariable/{code}.html")
	@ResponseBody
	public String urlTestId(@PathVariable String code) {
		return code;
	}

6.2.5. @ModelAttribute

@ModelAttribute 處理 HTML FORM POST 提交

		
package cn.netkiller.pojo;

import java.util.List;

public class Deploy {

	private String group;
	private String envionment;
	private String project;
	private List<String> arguments;
	public Deploy() {
		// TODO Auto-generated constructor stub
	}
	// Getters & Setters
}
		
		
		
	@RequestMapping(value="/deploy/post",  method = RequestMethod.POST)
	public ModelAndView post(@ModelAttribute("deploy")Deploy deploy, BindingResult result) {
		if (result.hasErrors()) {
			System.out.println(result.toString());
        }
		System.out.println(deploy.toString());
		return new ModelAndView("output").addObject("output", deploy.toString());
	}

6.2.6. @ResponseBody

		
import org.springframework.web.bind.annotation.ResponseBody;

6.2.6.1. 直接返回HTML

			
package cn.netkiller.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class Pathinfo {

	@RequestMapping(value = "/news/shenzhen/{numericId:[\\d]+}")
	@ResponseBody
	public String getNewsWithPathVariable(@PathVariable final long numericId) {
		return "Get a specific Bar with id=" + numericId;
	}

}

6.2.7. @ResponseStatus 設置 HTTP 狀態

		
	@RequestMapping(value = "/", method = RequestMethod.POST)
    @ResponseStatus(HttpStatus.CREATED)
    public String create(@RequestBody MultiValueMap<String, String> map) {
        return "OK";
    }

6.2.8. @CrossOrigin

		
	@CrossOrigin(origins = "http://localhost:9000")
	@GetMapping("/greeting")
	public Greeting	greeting(@RequestParam(required=false, defaultValue="World") String name) {
		System.out.println("==== in greeting ====");
		return new Greeting(counter.incrementAndGet(), String.format(template,name));
	}		
		
		
		
@CrossOrigin(origins = "*", allowedHeaders = "*")
@RestController
public class HomeController
{
    @GetMapping(path="/")
    public String home() {
        return "home";
    }
}

全局放行所有輕鬆，方法權限單獨控制

		
@RestController
@CrossOrigin(origins = "*", allowedHeaders = "*")
public class HomeController
{
    @CrossOrigin(origins = "http://example.com")
    @GetMapping(path="/")
    public String home() {
        return "home";
    }
}

6.2.8.1. maxAge

			
@CrossOrigin(origins = {"http://localhost:8585"}, maxAge = 4800, allowCredentials = "false")
@RestController
@RequestMapping("/info")
public class PersonController {
	@Autowired
	private PersonService service;
	@CrossOrigin(origins = {"http://localhost:8080"}, maxAge = 6000)
	@RequestMapping("home")
	public List<Person> show() {
		List<Person> list = service.getAllPerson();
		return list;
 	}
}

6.2.9. @CookieValue - 獲取 Cookie 值

		
@RequestMapping("/sessionInfo")  
public void sessionInfo(@CookieValue("JSESSIONID") String cookie)  {

  //...  

}

6.2.10. @SessionAttributes

@SessionAttributes: 該註解用來綁定HttpSession中的attribute對象的值，便于在方法中的參數里使用。 該註解有value、types兩個屬性，可以通過名字和類型指定要使用的attribute 對象； 

		
@Controller  
@RequestMapping("/editProfile")  
@SessionAttributes("profile")  
public class ProfileForm {  
    // ...  
}  
		
		
		
@Controller
@SessionAttributes("myRequestObject")
public class MyController {
  ...
}

6.2.11. ModelAndView

6.2.11.1. 變數傳遞

			
@RequestMapping("/testString")
public ModelAndView	helloWorld() {
	String message = "Helloworld!!!";
	return new
	ModelAndView("welcome", "message", message);
}			
			
			
			
public ModelAndView handleRequestInternal() {

	ModelAndView mav = new ModelAndView("test");//
	實例化一個VIew的ModelAndView實例
	mav.addObject("variable", "Hello World!");//
	添加一個帶名的model對象
	return mav;
}

6.2.11.2. ModelMap 傳遞多個變數

傳遞多個字元串

			
@RequestMapping("/testModelMap")
public ModelAndView	testModelMap() {
	ModelMap model = new ModelMap();

	model.addAttribute("username", "Neo");
	model.addAttribute("password", "Netkiller");

	return new ModelAndView("test/modelmap", model);
}

推薦使用ModelMap

			
	@RequestMapping("/testMapString")
	public ModelAndView testMapString() {

		Map<String,String> data = new HashMap<String,String>();
		data.put("username","Neo");
		data.put("password","Netkiller");
	    return new ModelAndView("test/modelmap",data);

	}
			
			
			
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
${username}<br>
${password}<br>
</body>
</html>

6.2.11.3. redirect

			
	@RequestMapping("/testRedirect")
	public ModelAndView testRedirect(){
		   RedirectView view = new RedirectView("testMapString.html");
		   return new ModelAndView(view);
	}

6.2.11.4. ArrayList

			
	@RequestMapping(value = "testList")
	public ModelAndView testList() {
		ModelAndView mav = new ModelAndView();
		mav.setViewName("/test/list");

		// List
		List<String> list = new ArrayList<String>();
		list.add("java");
		list.add("c++");
		list.add("oracle");
		mav.addObject("bookList", list);

		return mav;
	}
			
			
			
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
	pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
	${bookList}
	<br>

	<c:forEach items="${bookList}" var="node">
		<c:out value="${node}"></c:out><br>
	</c:forEach>

</body>
</html>

6.2.11.5. HashMap

			
	@RequestMapping("/testMap")
	public ModelAndView testMap() {
		ModelAndView mav = new ModelAndView();
		mav.setViewName("test/map"); // 返回的檔案名

		// Map
		Map<String, String> map = new HashMap<String, String>();
		map.put("Java", "http://www.netkiller.cn/java");
		map.put("PHP", "http://www.netkiller.cn/php");
		map.put("Home", "http://www.netkiller.cn");
		mav.addObject("channel", map);

		return mav;
	}
			
			
			
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
	<c:forEach items="${channel}" var="node">
		<a href="<c:out value="${node.value}"></c:out>"><c:out value="${node.key}"></c:out></a>
        <br/>
	</c:forEach>
</body>
</html>

6.2.11.6. 傳遞對象

			
	@RequestMapping("/testObject")
	public ModelAndView testObject() {
		ModelMap model = new ModelMap();

		User user = new User("neo", "passw0rd");
		model.addAttribute("user", user);
		return new ModelAndView("test/object", model);

	}
			
			
			
package cn.netkiller;

public class User {
	public String username;
	public String password;
	public User(String username, String password){
		this.username = username;
		this.password = password;
	}
	public String getUsername(){
		return this.username;
	}
	public String getPassword(){
		return this.password;
	}
}
			
			
			
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
Username: ${user.username}<br>
Password: ${user.password}<br>
</body>
</html>

6.2.11.7. 

6.2.12. HttpServletRequest / HttpServletResponse

6.2.12.1. HttpServletResponse

HttpServletResponse 實例

			
package cn.netkiller.api.rest;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import api.util.MatrixToImageWriter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Hashtable;

@Controller
@RequestMapping("/public/QRCode")
public class QRCodeController {
    private static final Logger log = LoggerFactory.getLogger(QRCodeController.class);
	
    @RequestMapping("/create/{code}" )
    @ResponseBody
    public void create(@PathVariable String code, HttpServletResponse httpServletResponse) throws WriterException, IOException {
        log.info(code);
        if (code != null && !"".equals(code)){
            ServletOutputStream stream = null;
            try {
                String text = code; 	// 二維碼內容
                int width = 300; 		// 二維碼圖片寬度
                int height = 300; 		// 二維碼圖片高度
                String format = "gif";	// 二維碼的圖片格式

                Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();
                hints.put(EncodeHintType.CHARACTER_SET, "utf-8");   // 內容所使用字符集編碼

                BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
                // 生成二維碼
                stream = httpServletResponse.getOutputStream();
                MatrixToImageWriter.writeToStream(bitMatrix, format, stream);

            }catch (WriterException e) {
                e.printStackTrace();
            } finally {
                if (stream != null) {
                    stream.flush();
                    stream.close();
                }
            }
        }
    }

    @RequestMapping("show")
    @ResponseBody
    public ModelAndView show(){

        return new ModelAndView("/qrcode/qrcode");
    }
}

6.2.12.2. HttpServletRequest

			
package com.example.demo.controller;

import java.io.IOException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api/test")
public class TestController {

	public TestController() {
		// TODO Auto-generated constructor stub
	}

	@GetMapping("/get")
	public String get(@RequestHeader String lang) throws IOException {
		System.out.println(lang);
		return lang;
	}

	@PostMapping("/post")
	public String post(@RequestHeader String lang) throws IOException {
		System.out.println(lang);
		return lang;
	}

	@GetMapping("/list")
	public Map<String, String> x(HttpServletRequest request) throws IOException {

		return getHeadersInfo(request);
	}

	private Map<String, String> getHeadersInfo(HttpServletRequest request) {

		Map<String, String> map = new HashMap<String, String>();

		Enumeration<?> headerNames = request.getHeaderNames();
		while (headerNames.hasMoreElements()) {
			String key = (String) headerNames.nextElement();
			String value = request.getHeader(key);
			map.put(key, value);
		}

		return map;
	}

}

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第 6 章 Spring MVC 起始頁 6.3. @RestController